Prefabricated metal stairway

ABSTRACT

A prefabricated, totally self-supporting metal exterior stairway, for use in connection with a two-story building, is built upon a rectangular load-distributing, ground-bearing frame. Two opposed runs of steps are provided. One run leads from grade to a landing, supported on a rigid box-like support, the loads from which are posted to the ground-bearing frame. The other run leads from the landing to the second floor level. Newel posts link the steps to the ground-bearing frame and internal rigidity is provided by triangulation of members. Treads are of a type which permits field installation of a permanent tread surface.

United States Patent Raiguel, Jr.

[ 1 June 20, 1972 [54] PREFABRICATED METAL STAIRWAY [21] Appl.N0.:140,460

Calvert ..52/1 27 Wall Primary Examiner-Reinaldo P. MachadoAttorney-Barry Moyerman 57 ABSTRACT A prefabricated, totallyself-supporting metal exterior stairway, for use in connection with atwo-story building, is built upon a rectangular load-distributing,ground-bearing frame. Two opposed runs of steps are provided. One runleads from grade to a landing, supported on a rigid box-like support,the loads from which are posted to the ground-bearing frame. The otherrun leads from the landing to the second floor level. Newel posts linkthe steps to the ground-bearing frame and internal rigidity is providedby triangulation of members. Treads are of a type which permits fieldinstallation of a permanent tread surface.

2 Claims, 2 Drawing Figures BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to metallic building structures. Moreparticularly, it relates to prefabricated stairs suitable for exterioruse in connection with two-story buildings.

2. Prior Art Traditionally, stairways for multi-story buildings havebeen located inside stair wells. At one time, these were built in-situby erecting the walls of the stair well followed by installation oflandings and runs of steps.

In more recent times, such techniques have given way to those describedand illustrated in US. Pat. Nos. 3,052,332 and 3,228,154. These patentsutilize modular parallelepipedal frame works within which are providedsets of stairs, complete with landings. These modules are stacked to thedesired height and the building erected around them while they serve asscaffolding and masonry guides. Necessary tie-in connections are made tothe masonry as erection proceeds.

The parallelepipedal shape, while desirable in such applications, is notnecessarily economical. Further, the size of steel members used if themodules are to be truly interchangeable, must be selected on theassumption that a given module will be on the bottom and thus berequired to support the entire weight of all of the upper modules. Theinherent disad vantages of this approach are discussed in column 1 ofUS. Pat. No. 3,l75,654.

It has become increasingly apparent that current constructiontechniques, despite their alleged modernity, have not permitted growthof the housing industry consistent with our nation's need for housing.In May of 1969, HUD Secretary George Romney announced operationBreakthrough, a program of wide scope aimed at improving the entireprocess of supplying quality housing in decent living environments forall Americans. A need of that program, albeit a minor one, has been foran inexpensive exterior metal prefabricated stairway to give access tothe second floor of two story buildings such as, for example, gardenapartments. Desiderata for such a stairway include inherent rigidity,economic use of materials, safety, and elimination of the need for tyingto foundations or masonry to insure support. Further, unlike the stairsshown in patents like US. Pat. No. 3,175,654, such stairs should notrequire the provision of a stair well nor place any heavy reliance uponcrafts other than that of the metalworker.

SUMMARY OF THE INVENTION Briefly, the invention comprises a generallyrectangular round-bearing base upon one end of which a rigid, box-likelanding support structure is erected. The landing itself is at anelevation midway between grade and the second floor level. A first runof steps leads from the framework, at the end opposite the landingstructure, to the landing. This run of steps, which includes stringers.serves to further brace the landing structure. A second run of stepsleads from the landing to the second floor level in a directiondiametrically opposed to the first run. Newel posts carry the verticalloads down to the framework from the terminus of the second run. One ofthese is shared by the first run to define an internal triangular trusshaving the common newel post as its base and coplanar edges of the tworuns of steps as its sides. Conventional balustrades and hand rails areprovided.

Accordingly, it is an object of the invention to provide a rigid, stronginternally braced prefabricated metal stairway which meets thedesiderata set forth above.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, wherein like referencenumerals designate like parts:

FIG. 1 represents an isometric view of a stairway embodying theinvention with a portion of the steps cut away.

FIG. 2 is a fragmentary section taken on line 2--2 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The metal exterior stairwayshown in FIG. 1 comprises a generally rectangular ground-bearing base,generally A, at one end of which there is mounted a rigid box-likelanding structure B. A first run of steps, C, extends from the other endof the base to the landing structure and a second run of steps, D,extends from said structure to the second floor level where it abuts anappropriate opening in a building (not shown). Other miscellaneousmembers, such as newels, which complete the structure will be discussedindividually below.

Base A is generally rectangular and is made up of members which extendlongitudinally (direction 10) and transversely (direction 11). Theseinclude, particularly, a front transverse member 12, a rear transversemember 13, at left longitudinal member 14 and a right longitudinalmember 15. Member 14 has been broken away to reveal its angularconstruction, a preferred cross-section. The base may be mounted on aconcrete pad or on footings.

The landing structure B includes a plurality of vertically extending(direction 16) members which partially define its boxlike configuration.As shown, these include newel posts 20 and 21 which are mounted at eachcomer of base A. These extend down to the ground level and are welded orotherwise secured to the base. Cooperating with these newel posts arepaired, transversely aligned posts 22 and 23 which are also attached toframe A. Were the landing greater in longitudinal (10) extent, otherpaired newel posts could be utilized. A plurality of horizontal channelsconnect these posts, at the desired elevation, to form an open rigidframe parallel to base A. These channels include member 24 (betweenposts 20 and 22), member 25 (spanning from post 22 to post 23), member26 (spanning from post 23 to post 21) and member 27 (spanning from post21 to post 20). A deck plate 28, mounted on the frame defined by members24, 25, 26 and 27, acts as the landing surface and is preferably ofnon-skid configuration. A short newel post 29 is also provided which isaffixed to member 25.

A first run of steps, generally C, extends from transverse member 12 tolanding member 25. This run is provided with a short newel post 32 and along newel post 33, which latter extends the full height of thestructure; The steps themselves include a plurality of treads, generally34, each having a base 35, a front upturned flange 36 and a rearupturned flange 37, as shown in FIG. 2. These treads are affixed to andspan between parallel stringers 38 and 39.

A second run of steps, generally D, extends from landing member 25 tothe second floor level and is of generally similar construction. ltstenninus is supported in part by previously mentioned post 33, which itshares with run C, and in part by a newel post 40 which also extendsvertically for the full height of the structure. The treads 34 of secondrun D are affixed to and span between parallel channels or stringers 41and 42.

As best seen in FIG. 2, the design of the treads is unique since thegenerally U-shaped configuration of tread 34 and adjacent stringerportions (e.g., 38 and 39) cooperate to comprise a tray adapted to befilled with material which fonns a finished permanent tread surface. Forexample, if concrete 43 is used it may incorporate non-skid surfacematerial, be poured in the field after the steps are installed andrenewed from time to time. Other materials including wood are obviouslyalso suitable.

The stairway is provided, as is customary, with a plurality of balusters44, which support related rails 45. These are connected to appropriatenewels and other structural members, as

shown.

Rigidity comes from the box-like nature of structure B and from internaltriangulation. Member 14, post 22 and stringer 38 provide one suchinternal integral truss. Another, on the medial plane, is provided bystringers 39 and 41 in combination with post 33. Elements 40, 15, 23 and42 also are similarly cooperative. The stairs thus provided are rugged,economical, rigid, easy to install and low in cost.

It will be understood that modifications and variations may I claim: 1.A prefabricated permanent metal exterior stairway for a two-storybuilding comprising:

a generally rectangular ground-bearing base having longitudinal membersand transverse members, said base being adapted to uniformly distributea vertical load about the perimeter thereof;

a landing structure at one end of said base including verticallyextending newel posts mounted at each comer of said base and paired,transversely aligned, vertically extending newel posts, one of each pairmounted on each longitudinal base member, horizontal channels connectingsaid newel posts intermediate their ends to define an open frame whichis parallel to said base and vertically spaced intermediate the firstand second floor levels, and a deck mounted on said frame to constitutea landing;

a first run of steps extending from the transverse member at the end ofthe base opposite said landing structure, to said landing;

a second run of steps, extending from said landing to the second floorlevel;

newel posts, linked to the transverse base member at which said firstrun originates, said posts supporting the terminus of said second runand one of said posts being common to the ground level of said first runand the top of said second run; said stairway thus posting all of itsloads to said base and having a triangulation rigidity including thatattributable to the internal trussing provided by the co-planar presenceof the edges of the two runs of stairs and a common newel post.

2. The stairway of claim 1 wherein each run of steps includes a pair ofparallel stringers and a plurality of treads, spanning said stringers,said treads having a generally U- shaped cross-section and each of saidtreads and its adjacent stringer portions comprising a tray adapted tobe filled with material which fonns a finished, permanent tread surface.

1. A prefabricated permanent metal exterior stairway for a twostorybuilding comprising: a generally rectangular ground-bearing base havinglongitudinal members and transverse members, said base being adapted touniformly distribute a vertical load about the perimeter thereof; alanding structure at one end of said base including vertically extendingnewel posts mounted at each corner of said base and paired, transverselyaligned, vertically extending newel posts, one of each pair mounted oneach longitudinal base member, horizontal channels connecting said newelposts intermediate their ends to define an open frame which is parallelto said base and vertically spaced intermediate the first and secondfloor levels, and a deck mounted on said frame to constitute a landing;a first run of steps extending from the transverse member at the end ofthe base opposite said landing structure, to said landing; a second runof steps, extending from said landing to the second floor level; newelposts, linked to the transverse base member at which said first runoriginates, said posts supporting the terminus of said second run andone of said posts being common to the ground level of said first run andthe top of said second run; said stairway thus posting all of its loadsto said base and having a triangulation rigidity including thatattributable to the internal trussing provided by the co-planar presenceof the edges of the two runs of stairs and a common newel post.
 2. Thestairway of claim 1 wherein each run of steps includes a pair ofparallel stringers and a plurality of treads, spanning said stringers,said treads having a generally U-shaped cross-section and each of saidtreads and its adjacent stringer portions comprising a tray adapted tobe filled with material which forms a finished, permanent tread surface.